Summer flounder, Paralichthys dentatus, culture is becoming increasingly popular in the United States because of high market prices and consumer demand. In addition, flounder is a marine fish species that can tolerate a wide range of salinities, allowing for inland intensive fish culture. Oxytetracycline (OTC) is one of two available FDA-approved antibiotics for use in foodfish in the United States. Oxytetracycline was chosen for these studies because it is excreted primarily unchanged through the urine and the absorption, distribution and elimination of this drug may be influenced by environmental and physiological conditions. Four experiments were conducted to investigate: 1) pharmacokinetic parameters of oxytetracycline (50 mg/kg) following intravascular (IV), intraperitoneal (IP), intramuscular (IM) and per os (PO) administration in summer flounder maintained at 28 ppt salinity and 20°C; 2) pharmacokinetic parameters of OTC (50 mg/kg) following IM and PO administration in summer flounder maintained at three different salinity levels of 0 ppt, 15 ppt and 32 ppt and the physiological adjustments summer flounder make to acclimate to environmental salinity; 3) OTC retention times in muscle tissue from summer flounder maintained at three different salinity levels (0 ppt, 15 ppt, 32 ppt) and treated with a single 50 mg/kg OTC dose via IM and PO administration; and 4) pharmacokinetic parameters of OTC (50 mg/kg) following IM and PO administration in clinically healthy and clinically diseased summer flounder maintained at 28 ppt and 20°C. Oxytetracycline plasma concentrations were determined using high performance liquid chromatography (HPLC) and analyzed using a non-compartmental pharmacokinetic model for all routes of drug administration. Statistical comparisons were not made between the different routes of OTC exposure, but results from experiment one indicated that IV administration of OTC resulted in the largest area under the curve (AUC) value (8147.9 µg·h/ml) and the highest maximum plasma concentration (Cmax) of 1173.2 µg/ml OTC at 5 min post-injection. Intramuscular injections of OTC resulted in prolonged total body elimination half-life (T ½) of 301.3 h and high fish-to-fish variability (0.6). Per os administration resulted in low Cmax (0.2 µg/ml OTC) and poor systemic bioavailability (0.2 %). Results from experiment two demonstrated that when OTC is administered IM AUC estimates are significantly (p<0.05) lower in summer flounder held at 0 ppt (1684.8 µg·h/ml) than fish maintained at 15 ppt or 32 ppt salinity (2067.8 µg·h/ml and 2241.3 µg·h/ml, respectively). Although not significantly different from other salinity treatments, time to maximum plasma concentration (Tmax) was longer in fish held at 15 ppt and 32 ppt (312 h and 168 h, respectively) compared to cohorts in freshwater (0.5 h) and Cmax values were higher in animals held at 15 ppt and 32 ppt (8.4 µg/ml OTC and 9.2 µg/ml OTC, respectively) than freshwater fish (4.9 µg/ml OTC) when OTC was administered via IM injection. No significant differences were detected in any of the pharmacokinetic parameters following PO dosing of OTC, however, the AUC estimates were lower in the 32 ppt acclimated fish (127.7 µg·h/ml) than in the 0 ppt or 15 ppt acclimated fish (190.2 µg·h/ml and 180.7 µg·h/ml, respectively). In addition, the T ½ was longer in the higher salinity groups (278.1 h and 266.0 h, respectively) than in the freshwater fish group (256.9 h). Physiological adjustments made by summer flounder including plasma and urine osmolality, urine flow rate and urine character, gill chloride cell size and density, and Na+ - K+ ATPase activity demonstrated trends that suggested physiological differences among the salinity groups. Plasma and urine osmolalities were typically significantly (p<0.05) higher in fish maintained at 32 ppt salinity than at the lower salinity treatments. In addition, urine flow rates were generally significantly (p<0.05) greater in freshwater adapted fish (0.13 - 0.21 ml of urine/kg/hour) in comparison to fish in the salinity treatments of 15 ppt and 32 ppt (0.06 - 0.12 ml of urine/kg/hour and 0.09 – 0.11 ml of urine/kg/hour, respectively). Changes in gill chloride cell size and density and enzyme activity of Na+ - K+ ATPase revealed no significant differences between the salinity treatments but summer flounder in saltwater had numerically larger and more chloride cells than summer flounder in freshwater, but enzyme activity was greater in freshwater acclimated summer flounder compared to fish in seawater. Experiment three results revealed similar OTC muscle tissue pharmacokinetic parameters in summer flounder following IM injection. However, there were significant differences (p<0.05) in the AUC parameters of the plasma and muscle OTC concentrations between fish maintained at different salinities following IM OTC treatment. These effects may be the result of a "depot" effect in the muscle tissue or may be related to the reduced solubility of OTC in the muscle tissue of marine fish. A single PO dose administration of OTC at 50 mg/kg did not result in plasma or tissue concentrations higher than the FDA tissue tolerance limit of 2 ppm. Results of the fourth experiment demonstrated that following IM OTC administration healthy fish had significantly (p<0.05) higher AUC (4700.6 µg·h/ml) values than diseased cohorts (2576.2 µg·h/ml). Maximum plasma concentrations were also higher in the healthy fish than in the diseased fish, although values were not significantly different (23.4 µg OTC/ml and 20.2 µg OTC/ml, respectively for healthy and diseased fish). Additionally, in diseased fish, the mean resident time (MRT) (293.7 h) and T ½ (203.5 h) parameters were longer compared to parameters in healthy fish (253.2 h and 175.4 h, respectively), although values were not significantly different. No significant differences were detected in any of the pharmacokinetic parameters following PO OTC administration, however, healthy fish achieved higher maximum plasma OTC concentrations (1.0 µg OTC/ml) than diseased fish (0.7 µg OTC/ml). Fish-to-fish variation was greater in diseased animals than in healthy regardless of route of drug administration. The results of these experiments indicated that OTC pharmacokinetic parameters are influenced by route of drug administration, environmental salinity and fish health status. These factors must be considered by veterinarians and governmental regulators when developing treatment regimens for summer flounder. / Ph. D.

When mining companies extract minerals from the earth, they leave huge deposits of soil and ore next to the mining site. These deposits are commonly known as tailings. In most instances, tailings contain a considerable amount of valuable mineral resources which cannot be exploited because of a lack of appropriate equipment, or as a result of economic non-viability. However, many mining companies choose to keep and maintain these tailings, in the hope that such minerals can later be exploited when time or technology allows for this. Under common-law the owner of a property is considered to also own any minerals contained on the property, in terms of the principle of cuius est solum. In South African law, however, a practice evolved whereby owners of minerals separated rights to minerals from the surface rights on the property. This created a mining right which was independent from the land and could be transferred to third parties, often in return for compensation. Under the Minerals Act of 1991 the owner of a mining right over a property (be that the owner of the property or a third-party mining right holder) also held the mining right to tailings which were created as a result of mining activities under the right. Thus, if a mining company performed mining activities on a property, the company was also free to exploit the tailings which were left next to its mine, regardless of whether the dump had remained there for a long period of time. Owing to South Africa's long history of mining, some tailings are over a century old and resemble small mountains rather than mining deposits. The Mineral and Petroleum Resources Development Act of 2002 changed the entire mineral legislative regime in South Africa. Whereas owners of land were previously free to separate and sell their rights to minerals to anyone they wished, the MPRDA placed the country‟s mineral and petroleum resources under the state's "custodianship." Where the law talks about custodianship, however, it supposedly refers only to minerals that have not yet been extracted from the earth. It is well established in South African law that, once a mineral is extracted, it becomes the movable property of the person who extracted it – in other words, that of the mining company. Does this mean that minerals in tailings also fall under the state's custodianship? The Free State High Court did not think so. In the case of De Beers v Ataqua it held that, in terms of the common law principles of acquisition by way of attachment, tailings are clearly movable property and therefore belong to the mining company who created them. For the MPRDA to hold otherwise would amount to expropriation. The state did not wish for some mining activities to be regulated by a different set of legislation, so it amended the MPRDA to try and define "residue deposits" (the name by which the MPRDA calls tailings) more clearly. However, due to the legislature's unfortunate choice of wording, tailings created before the enactment of the MPRDA are still, strictly speaking, not regulated by that Act. So the legislature proposed another amendment to the Act, this time making sure that any historical mine dump created at any point in South Africa's history are placed under the Act's regime. The subject matter of this study is whether the above amendments to the MPRDA could be considered to be expropriation. For background purposes, a brief overview of the Ataqua decision as well as the subsequent amendments to the MPRDA will be given. Then the history of mining legislation and the development of a separate mining right will be summarised. The reason for this summary is to establish whether, in terms of constitutional litigation, a clear right has been established for purposes of protection under section 25 of the Constitution. The last phase of the study will look at the particular characteristics of expropriation and ask the question whether acquisition of a right by the state is always a fundamental requirement for expropriation to take place. It is submitted that the destruction of an entire class of property by way of legislation, amounts to so-called "institutional expropriation," which is subject to compensation in terms of section 25. / LLM (Environmental Law and Governance), North-West University, Potchefstroom Campus, 2015

When mining companies extract minerals from the earth, they leave huge deposits of soil and ore next to the mining site. These deposits are commonly known as tailings. In most instances, tailings contain a considerable amount of valuable mineral resources which cannot be exploited because of a lack of appropriate equipment, or as a result of economic non-viability. However, many mining companies choose to keep and maintain these tailings, in the hope that such minerals can later be exploited when time or technology allows for this. Under common-law the owner of a property is considered to also own any minerals contained on the property, in terms of the principle of cuius est solum. In South African law, however, a practice evolved whereby owners of minerals separated rights to minerals from the surface rights on the property. This created a mining right which was independent from the land and could be transferred to third parties, often in return for compensation. Under the Minerals Act of 1991 the owner of a mining right over a property (be that the owner of the property or a third-party mining right holder) also held the mining right to tailings which were created as a result of mining activities under the right. Thus, if a mining company performed mining activities on a property, the company was also free to exploit the tailings which were left next to its mine, regardless of whether the dump had remained there for a long period of time. Owing to South Africa's long history of mining, some tailings are over a century old and resemble small mountains rather than mining deposits. The Mineral and Petroleum Resources Development Act of 2002 changed the entire mineral legislative regime in South Africa. Whereas owners of land were previously free to separate and sell their rights to minerals to anyone they wished, the MPRDA placed the country‟s mineral and petroleum resources under the state's "custodianship." Where the law talks about custodianship, however, it supposedly refers only to minerals that have not yet been extracted from the earth. It is well established in South African law that, once a mineral is extracted, it becomes the movable property of the person who extracted it – in other words, that of the mining company. Does this mean that minerals in tailings also fall under the state's custodianship? The Free State High Court did not think so. In the case of De Beers v Ataqua it held that, in terms of the common law principles of acquisition by way of attachment, tailings are clearly movable property and therefore belong to the mining company who created them. For the MPRDA to hold otherwise would amount to expropriation. The state did not wish for some mining activities to be regulated by a different set of legislation, so it amended the MPRDA to try and define "residue deposits" (the name by which the MPRDA calls tailings) more clearly. However, due to the legislature's unfortunate choice of wording, tailings created before the enactment of the MPRDA are still, strictly speaking, not regulated by that Act. So the legislature proposed another amendment to the Act, this time making sure that any historical mine dump created at any point in South Africa's history are placed under the Act's regime. The subject matter of this study is whether the above amendments to the MPRDA could be considered to be expropriation. For background purposes, a brief overview of the Ataqua decision as well as the subsequent amendments to the MPRDA will be given. Then the history of mining legislation and the development of a separate mining right will be summarised. The reason for this summary is to establish whether, in terms of constitutional litigation, a clear right has been established for purposes of protection under section 25 of the Constitution. The last phase of the study will look at the particular characteristics of expropriation and ask the question whether acquisition of a right by the state is always a fundamental requirement for expropriation to take place. It is submitted that the destruction of an entire class of property by way of legislation, amounts to so-called "institutional expropriation," which is subject to compensation in terms of section 25. / LLM (Environmental Law and Governance), North-West University, Potchefstroom Campus, 2015

No description available.

No description available.

This serves to introduce the present research and is chiefly historical. It deals briefly with methods of assessing the coking ability of coals and also with early modern, and contemporary investigations upon coke formation. The author's earlier work on the distillation of oil from coals is described fully since it forms both the starting point and the basis of the present research. This work showed the power of retention of oil which is capable of 'wetting' the surface of the coal, up to temperatures of 420 degrees C., was an essential characteristic of coking coals. Part II deals with attempts to add more oil mechanically to improve the coking performance of various coals.

A laboratory scale delayed coking process was used to produce petrol precursors, diesel precursors, methane rich gas, green and calcined coke from five previously untested South African heavy petroleum residues. The ash content of the heavy petroleum residues was found to be detrimental to the microstructure of the green coke and Coefficient of Thermal Expansion (CTE) of the calcined coke. The sulphur content of the calcined cokes produced was found to be in-line with typical global anode grade cokes. De-ashing of the feedstock would be necessary to produce anode grade fillers for the aluminium industry. The local production of anode grade coke would serve to reduce imports and supply the aluminium smelters on the east coast of South Africa. The heavy petroleum residues (also known as heavy fuel oil) are currently used as bunker fuel in the shipping industry and are responsible for substantial air pollution. Delayed coking of these residues could extend the production of petrol and diesel per barrel of imported crude oil and reduce the effect on South Africa’s balance of payments deficit and impact the environment in a beneficial manner with respect to carbon dioxide and sulphur emissions. The research also evaluated the replacement of heavy fuel oil with marine diesel produced by delayed coking of the former. Marine diesel was found to emit less sulphur oxides and have a higher energy density per unit of carbon dioxide emitted. While seawater scrubbing of the heavy fuel oil would be more cost effective in reducing the sulphur oxide emissions, it would not contribute to carbon dioxide reductions. The research created a hypothetical scenario to determine the required value of Clean Development Mechanism credits for a marine diesel replacement, were shipping to be incorporated under the Kyoto Protocol in future

Estimation of time since death is an important variable when investigating legal cases involving decomposing human remains; however it has been sparsely studied in controlled environments. Decomposition rates are largely influenced by external factors with temperature being the most critical factor. The decomposition rates can also be influenced by insect infestation, chemical residues, and burial, yet little research has been conducted to document how various factors alter the rate and process of decomposition. A common occurrence at human remains recovery sites is the deposit of residues from criminal activities such as gunpowder and explosives. This experiment will look at gunpowder residue’s effects on porcine remains and the insect infestation after exposure. This study was conducted in two phases: the 1st experiment being conducted in the late spring and the 2nd in the early fall. For each experiment two carcasses were covered with gunpowder residue while one carcass served as a control (no residue). The physical decomposition processes as well as ambient temperature were documented for each carcass. The results for the study showed variable findings between the control and experimental subjects. The insect infestation of the remains was consistent with the data from previous entomological studies conducted from areas of similar climate and terrain. Factors that may have influenced the results are discussed in reference to the effects of the gunpowder residue on the decomposing remains.

Graduation date: 1995

We consider a homogeneous pseudodifferential equation on a cylinder C = IR x X over a smooth compact closed manifold X whose symbol extends to a meromorphic function on the complex plane with values in the algebra of pseudodifferential operators over X. When assuming the symbol to be independent on the variable t element IR, we show an explicit formula for solutions of the equation. Namely, to each non-bijectivity point of the symbol in the complex plane there corresponds a finite-dimensional space of solutions, every solution being the residue of a meromorphic form manufactured from the inverse symbol. In particular, for differential equations we recover Euler's theorem on the exponential solutions. Our setting is model for the analysis on manifolds with conical points since C can be thought of as a 'stretched' manifold with conical points at t = -infinite and t = infinite.